1. Field of the Invention
The invention relates to a processing apparatus for the processing of exposed photographic film.
2. Background Description
Such an apparatus is described for example in EP-A No. 180 545 (U.S. Pat. No. 4,678,307). In order to assure the uniform wetting of the surface of the film in such an apparatus, retaining means are provided whereby the coil of film located on the spool may be expanded and contracted in a controlled manner. In the apparatus according to EP-A-180 545 these film retaining means are in the form of hooks. In another apparatus known for example from U.S. Pat. No. 4,586,803 two pointed barbs are provided; they are mounted at the lower end of the part of the apparatus containing the processing liquid and are protruding into the tank. The function of these hoods and barbs is to penetrate into the transport holes of the film perforations and to hold the film in this manner.
Film retaining means of this type are suitable for films with perforations and of a certain film format only. Furthermore, the capture and holding of perforated films is very often left to accident, in particular as different films frequently have different stiffnesses and the forward end is often curved differentially. These film retaining means are therefore operating in actual practice with a low degree of reliability. Further processing devices of this type are described in EP-A-197 002 (U.S. Pat. No. 4,678,309) and U.S. Pat. No. 4,678,308. These devices are equipped with profiles of varying thickness on the surface of an intermediate bottom of the part of the apparatus containing the processing liquid. This specific configuration of these profile elements is intended to effect the loosening and the gathering of a part of the wound film. In particular, the resulting pumping action is to cause the processing liquid to contact the surface of the film better and more uniformly. These profile elements cannot hold the film and furthermore, only part of the film on the spool is being loosened or gathered. In particular, the windings closest to the core of the spool are insufficiently expanded and wetted by the processing liquid.
The disadvantage of the aforedescribed film retaining means and profile elements is that the secure holding of the film and the controlled expansion and contraction of the entire film wound on the spool, are not assured. The uniformity of the wetting of the emulsion side of the film by fresh processing liquid is inadequate in the known devices.
A further processing apparatus is described in U.S. Pat. No. 4,702,582, which contains no film retaining means and consequently cannot make possible the controlled expansion and contraction of the wound film. Correspondingly, the uniformity of the wetting of the film surface by the processing liquid is very poor.
The foregoing illustrates limitations known to exist in present devices. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully described hereinafter.